There are 18 National Natural Landmarks in the U.S. state of Washington, out of nearly 600 National Natural Landmarks in the United States.
| Name |
Image |
Date |
Location |
County |
Ownership |
Description |
| Boulder Park and McNeil Canyon Haystack Rocks |
 |
1986 |
47°52′43″N 119°48′06″W / 47.878611°N 119.801667°W / 47.878611; -119.801667 |
Douglas |
Federal, state |
The most illustrative examples of glacial erratics in the United States. |
| Davis Canyon |
|
1986 |
48°14′38″N 119°45′06″W / 48.243775°N 119.751774°W / 48.243775; -119.751774 |
Okanogan |
State, private |
One of the largest and least disturbed examples of antelope bitterbrush-Idaho fescue shrub steppe remaining in the Columbia Plateau. |
| Drumheller Channels |
 |
1986 |
46°58′30″N 119°11′47″W / 46.975°N 119.196389°W / 46.975; -119.196389 |
Adams, Grant |
Federal, state, private |
Illustrates the dramatic modification of the Columbia Plateau volcanic terrain by late Pleistocene catastrophic glacial outburst floods. Includes Columbia National Wildlife Refuge. |
| Ginkgo Petrified Forest |
 |
1965 |
46°56′56″N 120°00′10″W / 46.948889°N 120.002778°W / 46.948889; -120.002778 |
Kittitas |
State |
Thousands of logs petrified in lava flows. Part of Ginkgo/Wanapum State Park. |
| Grand Coulee |
 |
1965 |
47°46′00″N 119°13′00″W / 47.766667°N 119.216667°W / 47.766667; -119.216667 |
Grant |
Federal, state, private |
An illustration of a series of geological events. |
| Grande Ronde Feeder Dikes |
|
1980 |
|
Asotin |
Private |
The best example of basalt dikes, the congealed feeder sources of the Columbia River basalt plateau. |
| Grande Ronde Goosenecks |
|
1980 |
|
Asotin |
Federal |
A 1,500-foot (460 m) deep canyon that follows a tortuous path along meanders. |
| The Great Gravel Bar of Moses Coulee |
|
1986 |
47°27′30″N 119°48′00″W / 47.458333°N 119.8°W / 47.458333; -119.8 (Moses Coulee) |
Douglas |
State, private |
Largest and best example of a pendent river bar formed by catastrophic glacial outburst floods that swept across the Columbia Plateau. |
| Kahlotus Ridgetop |
|
2011 |
|
Franklin |
State |
The best remaining example of the Central Palouse Prairie grassland subtheme. |
| Mima Mounds |
 |
1966 |
46°53′N 123°03′W / 46.89°N 123.05°W / 46.89; -123.05 (Mima Mounds) |
Thurston |
State |
A prairie containing unusual soil pimples of black silt-gravel. |
| Nisqually Delta |
 |
1971 |
47°06′31″N 122°42′11″W / 47.108611°N 122.703056°W / 47.108611; -122.703056 (Nisqually Delta) |
Pierce, Thurston |
Federal, state, tribal, private |
An unusually fine example of an estuarine ecosystem. Includes Nisqually National Wildlife Refuge. |
| Point of Arches |
 |
1980 |
48°14′47″N 124°42′01″W / 48.2464503°N 124.7002419°W / 48.2464503; -124.7002419 (Point of Arches) |
Clallam |
Federal |
An outstanding exhibit of sea action in sculpturing a rocky shoreline. A unit of Olympic National Park. |
| Rose Creek Preserve |
|
1984 |
|
Whitman |
Private |
The best remaining example of the aspen phase of the hawthorne-cow parsnip habitat type in the Columbia Plateau. Managed by The Nature Conservancy. |
| Sims Corner Eskers and Kames |
 |
1986 |
47°49′30″N 119°22′00″W / 47.825°N 119.366667°W / 47.825; -119.366667 |
Douglas |
Federal, state, private |
The best examples in the Columbia Plateau of landforms resulting from stagnation and rapid retreat of the ice sheet during the last glaciation. |
| Steptoe and Kamiak Buttes |
 |
1965 |
47°01′57″N 117°17′55″W / 47.0325°N 117.298611°W / 47.0325; -117.298611 |
Whitman |
State, county, private |
Isolated mountain peaks of older rock surrounded by basalt, rising above the surrounding lava plateau. |
| Umtanum Ridge Water Gap |
 |
1980 |
46°51′00″N 120°32′40″W / 46.85°N 120.544444°W / 46.85; -120.544444 |
Kittitas |
Federal, state, private |
Geologic formation that illustrates the processes of tectonic folding and antecedent stream cutting. |
| Wallula Gap |
 |
1980 |
46°02′40″N 118°56′48″W / 46.044444°N 118.946667°W / 46.044444; -118.946667 |
Benton, Walla Walla |
Federal, state, county, municipal |
The largest and most spectacular of several large water gaps through basalt anticlines in the Columbia River basin. |
| Withrow Moraine and Jameson Lake Drumlin Field |
 |
1980 |
47°41′15″N 119°37′29″W / 47.6875°N 119.624722°W / 47.6875; -119.624722 |
Douglas |
Federal, private |
The best examples of drumlins and the most illustrative segment of the only Pleistocene terminal moraine in the Columbia Plateau |
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